I found this in a Taringa post that contains a lot of humor related to GNU/Linux and is worth checking out 
1. You are 104 years old.
2. You don't want to change OS, and you don't want your grave desecrated.
3. You have been diagnosed with a terminal illness and have 2 days to live. It is preferable to spend them with the family.
4. You claim that because you never understood StarWars, or Star Trek, or Stargate, or Tron ... you won't understand Linux either.
5. You have no friends to rub in your face that you no longer use Windows.
6. You live in the most remote corner of Africa, in your tribe there are more serious problems than changing the Operating System.
7. You have short-term memory loss. Every 5 minutes you forget why you wanted to try Linux.
8. Linux has no minesweeper, which is the only thing you use your useless PC for.
9. You will miss formatting every two months. I wouldn't know what to do with all that free time.
10. You could never quit smoking, you never learned to drive a car, you never knew how to change a light bulb, much less, you can change the Operating System.